This invention relates generally to valve trains in internal combustion engines. More particularly, this invention relates to valve trains using rocker arms to actuate intake and exhaust valves in a diesel engine.
Internal combustion engines have rocker arms to actuate intake and exhaust valves, which permit air to enter and exhaust to leave each cylinder. There are separate rocker arms for each valve. Push rods cause the rocker arms to rotate or pivot and thereby actuate the valves. The push rods extend through the engine to connect to a camshaft. As the camshaft rotates, the push rods move the rocker arms to open and close the valves. The camshaft is designed to open and close the valves in conjunction with the cycling of the piston in the cylinder.
Some rocker arm designs are made from castings. To reduce the weight and bulkiness associated with castings, recent rocker arm designs are made of plate material. However, the plate designs require pre-assembly into a rocker arm assembly for ease of installation in the engine. A clip is used to pre-assemble the rocker arm assembly. The clips are difficult to install and often do not keep the rocker arm assembly together before installation. In addition, the contact point between the rocker arm and the valve in these designs does not remain level as the rocker arm rotates which causes wear on the surface of the valve assembly.
Accordingly, there is a need for a rocker arm assembly having pre-assembly capability and reduced wear on the valve assembly during operation.
The present invention provides a rocker arm assembly for mounting on a carrier in an internal combustion engine which can be pre-assembled and installed on the rocker carrier to thereby decreased engine manufacturing time and cost. The rocker arm assembly comprises a rocker arm, a fulcrum plate, a retaining clip, and a pivot ball that in cooperation with the retaining clip cooperatively connects the fulcrum plate and the rocker arm such that the pivot ball provides a pivot point for the rocker arm to pivot about and actuate at least one valve or valve bridge. The rocker arm further comprises a push rod cup, an aperture, a pivot ball cup, and a pivot foot. The fulcrum plate in the rocker arm assembly can be a dual fulcrum plate, which would hold two rocker arms, or an end fulcrum plate, which would hold a single rocker arm. Further, the rocker arms can be either an intake rocker arm or an exhaust rocker arm.